When Michael Ballack was brought to Chelsea in the summer of 2006, his mission was clear: win the Champions League. This was a club that had won the Premier League in consecutive years but failed to reach the Champions League final and, certainly in the mind of its owner, Roman Abramovich, would not without the addition of a galáctico or two. Cue the arrival of Ballack and Andriy Shevchenko on contracts equal in size to their reputations.

Until December 2007, the purchases had not come close to achieving what had been demanded of them. Whereas the Ukrainian striker seemed to have a running feud with Jose Mourinho over his inability to find his Milan form, an ankle injury ended Ballack's first season prematurely in April, causing him to miss the Champions League semi-final defeat to Liverpool and the FA Cup final victory over Manchester United.

Ballack's subsequent decision to have surgery in Germany without consultation with the Chelsea doctors angered Mourinho to the extent that he left him out of the squad for the Champions League group stages this season. The explanation given was it was better to have a fully fit reserve player than a recovering Ballack, but the underlying suspicion was that Mourinho wanted him sold, and that could only be achieved if he was not cup-tied in Europe.

How pleased Chelsea fans must be that he stayed. While Shevchenko's seemingly permanent residence on the bench now goes unremarked, Ballack has gradually found increasing levels of acceptance at the club since his return in December, playing such a major role in Chelsea's revival in the league that it came as a big surprise and had damning consequences for the team when Avram Grant left him out of the starting line-up against Tottenham in the Carling Cup final.

He has both thrived in Frank Lampard's uncharacteristic absences through illness and injury and dovetailed well with the England midfielder, no more so than when he scored the goal that last night sent Chelsea into their fourth Champions League semi-final in five seasons. It was Lampard's free-kick from the right that Ballack glanced into the far corner with customary emphasis, having timed his run to perfection and stolen a yard in front of his marker, Mehmet Aurélio.

When Ballack had his annus mirabilis in 2002 - orchestrating the unlikely runs of Bayer Leverkusen and Germany to the finals of the Champions League and World Cup respectively - it was his goalscroing knack that made his name around Europe. A large proportion of his 25 in 48 games that season came via his heading prowess, for which he has few midfield peers. Last night's was reminiscent of Gustavo Poyet, and at Chelsea there is no higher praise.

Having succeeded in the difficult task of silencing the boisterous away crowd - a welcome reverse of the norm - Lampard and Ballack dominated the midfield exchanges during the first half. They provided the support to Didier Drogba that Fenerbahce's scheming playmaker, Alex, tightly patrolled by Claude Makelele, could not for his centre-forward, Semih Senturk. Both assuming advanced starting positions, the Englishmen and German took it in turns to make penetrating runs beyond Drogba - Ballack striking a half-volley that was well saved by Volkan Demire, Lampard a brilliant interception away from latching on to Ballack's throughball.

Grant's preference for Ballack, Lampard and Makelele in midfield meant Michael Essien was consigned to right-back, an undoubted shame given his boundless energy. That energy was put to good effect in the final minutes as, having been pushed forward to right midfield after the introduction of Juliano Belletti, he surged to the byline past three players and squared for Lampard to score the second.

Despite winning the Bundesliga on four occasions, Ballack has yet to win an international competition with club or country. He was suspended for the World Cup final in 2002 and was accused of choking in his homeland as Bayern Munich consistently failed in Europe during his four seasons there. But his goal here kepts hopes alive of fulfilling his - and Chelsea's - dream this season.